The present invention relates to an immersion device for measuring the temperature of a melt with an optical fiber, preferably a metal coated optical fiber, in a metallurgical vessel.
An immersion device for measuring the temperature of a melt with an optical fiber in a metallurgical vessel is known from EP 2 799 824 A1. Specifically, EP 2 799 824 A1 discloses a robotic immersion device for measuring the temperature in a metallurgical vessel using a molten metal-immersed consumable optical fiber and immersion equipment capable of inserting a temperature device through a side wall of an EAF to a predictable molten steel immersion depth with a temperature-to-temperature measuring frequency of less than 20 seconds. The robotic immersion comprises a disposable guiding tube having an immersion end and a second end, opposite to the immersion end. An optical fiber can be partially arranged in the disposable guiding tube, whereby the inner diameter of the disposable guiding tube is larger than the outer diameter of the optical fiber which is, as a rule, metal coated. An elastic plug is arranged at the second end of or within the disposable guiding tube, whereby the optical fiber is fed through the elastic plug and whereby the elastic plug reduces a gap between the optical fiber and the disposable guiding tube. In a first phase, the optical fiber and the immersion end of the disposable guiding tube are immersed into the melt. In a subsequent second phase, the optical fiber is immersed with higher speed and deeper into the melt than the disposable guiding tube for measuring the temperature of the melt. In a subsequent third phase, the optical fiber is withdrawn from the melt and the disposable guiding tube is ejected into the melt. For a further temperature measurement, it is necessary to provide a further disposable guiding tube.
The robotic immersion device known from EP 2 799 824 A1 comprises encoders and inductive position devices for monitoring the position of the end of the fiber. Further, the robotic immersion device comprises two independent feeding motors combined with separate feeding controls, one for feeding the optical fiber and one for feeding the disposable guiding tube.
JP H09304185 (A) discloses a metallic sheath optic fiber for measuring the temperature of molten steel, wherein a sent length of the optic fiber is measured by a motor with encoder. A corresponding device is also known from JP H07151608 (A).
It is an objective of the present invention to improve the temperature measurement with an optical fiber in a metallurgical vessel.